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why do we see the same side of the moon

When we say that the Moon rotates, we don't mean relative to an observer on Earth, because we're also rotating. Maybe best is to think of it from the perspective of the Sun. If you were at the centre of the solar system, looking at the Earth, you'd see the Moon rotates once every 28 days or so. That also happens to be the amount of time it takes for the Moon to go all the way around the Earth, and that combination is why, on Earth, we always see the same side.

Note that I don't mean an observer on the surface of the Sun, because that's rotating too! I just mean an observer who's situated at the centre of the Sun (and can see through it). Defining rotation generally depends on to whom its relative. How long does it take for the Earth to show the same face to an observer on Mars? I doubt it's 365 days! But it also isn't useful.

What really counts is going around the Sun. To go a bit further, you might also wonder why the Moon always shows us the same face. It isn't just a co-incidence! It's because of. Basically, the Moon is sufficiently big and close to the Earth, so that the Earth pulls on the near side more strongly than the far side. The details are a bit long to reproduce here, but the result is that one side of the Moon always faces us. (Only approximately.

The Moon still wobbles a bit, so we end up able to see about 58% of its surface from here: see. ) The moon travels around the earth once every 29 days. The moon, attracted by the Earth s gravitational pull, travels with the earth and circles the sun every 365 days. The moon rotates completely on its axis (the imaginary line through its north and south poles) only once during each trip around the earth.

When we look at the moon, we always see the same side. This is because the moon turns once on its axis in the same time that it circles the earth. This motion is called synchronous rotation. Unlike the earth, which rotates 365 times during each rotation around the sun, the moon only rotates once. This results is your observation. only one side can ever be seen from a specific point on earth.